The present invention relates to absorbent articles, and more particularly to disposable absorbent articles having a gradation in color intensity visible when the article is worn.
The present invention is applicable to many different types of absorbent articles, including training pants, diapers, incontinence products, diaper pants, disposable underwear, medical garments, absorbent swim wear, and the like. It is especially (albeit not exclusively) suited to articles used in the toilet training process, a process which includes many training techniques and training aids that may be used by parents and caregivers (hereinafter simply referred to as caregivers). One aspect of the total toilet training process is the change from diapers to training pants to help the child understand that he or she should now use the toilet just like adults. Although the use of training pants and positive encouragement from the caregiver has been helpful in the toilet training process, there is still much room for improvement. Specifically, caregivers are still searching for easier and quicker ways to guide their children successfully through the toilet training process.
Many caregivers underestimate the difficulty of teaching the toilet training process to young children. If a child does not respond to an initial toilet training instruction or introduction, the caregiver can be at a loss for finding techniques, methods, or teaching tools to encourage the child to master the art of toilet training. Thus, while various teaching tools such as books, videotapes, charts with stickers, personalized toilets, and interactive toilet training kits are available, there remains a need for improved motivational mechanisms to facilitate the toilet training process.
One motivational mechanism is the use of training pants having an improved aesthetic appearance. Specifically, a child is encouraged to wear a garment which resembles underwear worn by older children or resembles outer garments worn by adults. These articles can have a moderately darker color or a color pattern on their front and back sides. Further, they may have a graphic, emblem, or pictorial image which is complemented by a background color, at least a portion of which is of moderate intensity. Unfortunately, most training pants have a solid light color or pastel background on their front and back sides, which can appear to be “babyish” to the child or otherwise fail to motivate the child to wear the garment.
Another motivational mechanism is the use of active graphics. As used herein, the term “active graphic” refers to an appearing graphic, a fading graphic, or a combination of fading and appearing graphics. The term “appearing graphic” is used herein to refer to a graphic that becomes visible or becomes significantly more visible when exposed to urine, or that becomes visible or becomes significantly more visible with the passage of time when exposed to the environment but not exposed to urine. Conversely, the term “fading graphic” is used herein to refer to a graphic that becomes invisible or becomes significantly less visible, or the color(s) “run” to obscure the graphic design, when exposed to urine, or that becomes invisible or becomes significantly less visible with the passage of time when exposed to the environment but not exposed to urine.
Active graphics should ideally be used on a lightly colored or white background. A darker background can obscure visibility of the graphics and/or obscure the mechanism of appearing or fading.
An active graphic can comprise a fading graphic which is formed from an ink that is soluble in aqueous solutions such as urine. The ink is positioned in the absorbent article so that it becomes wet and dissolves when the product is insulted with liquid. Once dissolved, or the colors(s) run, the ink washes away from the substrate on which it is printed and is obscured by the process of “running”. As a result, the active graphic seems to disappear from view.
Suitable urine-soluble inks are available from a variety of commercial vendors, such as Sun Chemical Corp. of Philadelphia, Pa., USA under the trade designation AQUA DESTRUCT. Particular urine-soluble compositions are disclosed in U.S. Pat. No. 4,022,211 issued May 10, 1977 to Timmons et al., which is incorporated herein by reference. The ink color can be selected to provide a pleasing appearance and graphic impact, including fading rapidly upon contact with liquid. To facilitate rapid fading, the fading graphics can comprise line drawings having a line width of from about 1 to about 2 millimeters.
The active graphic can also comprise a fading or an appearing graphic which is formed from a composition such as an ink or adhesive that changes color when exposed to an aqueous solution such as urine. A color change composition can be adapted to blend in with a background or surrounding color, either before or after exposure to the aqueous solution. Suitable compositions of this color-change type are available from a variety of commercial vendors, such as a pH-change/color-change hot melt adhesive available from Findley Adhesives, Inc. of Wauwatosa, Wis., USA. Alternatively, the active graphic can comprise pH sensitive inks, fugitive inks, colored absorbent particles, hydratable salts, moisture sensitive films, enzymes, heat sensitive inks and dyes, or the like.
Fading graphics can simply disappear from view, relative to the exterior surface of the outer cover. The active graphic can also be configured to appear over time due to exposure to the environment. In particular, the active graphic can be responsive to time intervals, temperature levels, oxygen levels, or the like, and combinations thereof. Various visual indicators that appear over time in response to particular conditions are disclosed in U.S. Pat. No. 5,058,088 issued Oct. 15, 1991 to Haas et al.; U.S. Pat. No. 5,053,339 issued Oct. 1, 1991 to Patel; U.S. Pat. No. 5,045,283 issued Sep. 3, 1991 to Patel; U.S. Pat. No. 4,987,849 issued Jan. 29, 1991 to Sherman; U.S. Pat. No. 4,903,254 issued Feb. 20, 1990 to Haas; U.S. Pat. No. 4,812,053 issued Mar. 14, 1989 to Bhattacharjee; and U.S. Pat. No. 4,292,916 issued Oct. 6, 1981 to Bradley et al.; all of which are incorporated herein by reference. An active graphic that appears over time may be applied to the product when use is initiated, or formed as an integral component of the product.
In contrast to active graphics, the term “permanent graphic” is used herein to refer to a graphic that does not substantially change its degree of visibility when the absorbent article is insulted with urine and when the absorbent article is exposed to the environment, in actual or simulated use conditions.
The graphics of the absorbent article can be constructed to provide a story line involving a permanent character graphic and an active object graphic. The term “character graphic” is used herein to refer to a graphic containing an anthropomorphous image, and in particular an image having or suggesting human form or appearance which ascribes human motivations, characteristics or behavior to inanimate objects, animals, natural phenomena, cartoon characters, or the like. Suitable character graphics can include animals, people, inanimate objects, natural phenomena, cartoon characters, or the like that can or can not be provided with human features such as arms, legs, facial features or the like. For purposes of enhanced toilet training, it may be desirable for the character graphic to be familiar to the child, such as an identifiable cartoon character. The character graphics should at least be a type that the child can relate to, examples of which could include animals, toys, licensed characters, or the like. Character graphics can be made more personable and friendly to the child by including human-like features, human-like expressions, apparel, abilities, or the like. By way of illustration, an animal character graphic can be shown smiling, wearing clothing, playing sports, fishing, driving, playing with toys, or the like. In particular embodiments, the character graphic can desirably be created to project an appearance that could be described as friendly, positive, non-intimidating, silly, independent, inspirational, active, expressive, dauntless and/or persevering.
As referenced above, the permanent character graphic is desirably interactively interrelated with the active object graphic. The term “object graphic” is used herein to refer to a graphic representing an object or thing, which can include an inanimate object or a character. As used herein, “visible area” refers to structure or features externally visible while the absorbent article is worn.
For more detail regarding active graphics and their construction and operation, reference may be made to published PCT applications No. PCT/US00/16540 (Pub. No. WO 00/76438), entitled “Absorbent Articles Incorporating Color Change Graphics”, No. PCT/US00/16542 (Pub. No. WO 00/76439), entitled “Absorbent Articles Having Wetness Indicating Graphics Incorporating a Training Zone”, No. PCT/US00/16405 (Pub. No. WO 00/76442), entitled “Absorbent Articles Having Wetness Indicating Graphics Providing An Interactive Training Aid”, and No. PCT/US00/16539 (Pub. No. WO 00/76443), entitled “Absorbent Articles Having Wetness Indicating Graphics and Employing Masking Techniques”. These applications are assigned to Kimberly-Clark Worldwide, Inc., and are fully incorporated by reference herein for all purposes.
While the above improvements represent significant advances in the toilet training process, there is an ongoing need to increase the appeal of the toilet training process to children, and to improve the aesthetic appearance of disposable absorbent articles used in this process and other applications. It is advantageous for garments resemble underwear worn by older children. However, it is important that any modifications to the articles to meet these needs not compromise the use of the articles or any functional features of the articles (e.g., the wetness indicators).